Huntington's disease is a fatal, inherited neurodegenerative disorder caused by a mutation in the gene encoding huntingtin. Expresion of mutant huntingtin (mHTT) protein is correlated with the onset and progression of the disease and new therapies are being developed to reduce the expression of mHTT. In order to evaluate these new therapies, researchers need to be able to quantify the amount of mHTT in a particular patient; however, non-invasive quantification of mHTT isn't currently possible.